Predictors of vitamin B6 and folate concentrations in older persons: the InCHIANTI study.

BACKGROUND: Low dietary intake and low serum concentrations of vitamin B6 and/or folate are associated with increased risk of vascular events, possibly because of their association with inflammation, which plays a crucial role in the pathogenesis of cardiovascular diseases. METHODS: Using data from 1320 participants in the population-based InCHIANTI study (586 men and 734 women; median age, 69 years; range, 21-102 years) for whom complete data on folate, vitamin B6, inflammatory markers, 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T sequence variant, and important covariates were available, we evaluated the association of inflammatory markers with circulating concentrations of vitamin B6 and folate, independently of dietary vitamin intake, circulating vitamin concentrations, and MTHFR C677T sequence variant. RESULTS: According to multiple linear regression analysis, C-reactive protein and interleukin-6 receptor were strongly and negatively associated with circulating vitamin B6 but not with folate concentrations, independent of age, sex, serum creatinine, serum albumin, total energy intake, smoking history, dietary nutrient intake, and circulating homocysteine and vitamin concentrations. Serum folate concentrations were related to MTHFR 677 TT genotype in persons with folate intake in the lowest tertile (< 221.2 microg/day). Vitamin C and retinol intakes were strongly and positively associated with serum folate concentrations independent of age, sex, serum creatinine, serum albumin, total energy intake, smoking history, homocysteine plasma concentrations, dietary nutrient intakes, serum vitamin B6 and vitamin B12 concentrations, and MTHFR C677T sequence variant. CONCLUSIONS: Low serum vitamin B6, but not serum folate, concentrations are independent correlates of the proinflammatory state, and both are influenced by antioxidant reserves.

A proinflammatory state is associated with hyperhomocysteinemia in the elderly.

BACKGROUND: The mechanism by which high circulating homocysteine concentrations are a risk factor for atherothrombosis is incompletely understood. A proinflammatory state is related to atherosclerosis, and recent studies suggest that acute phase reactants correlate with circulating concentrations of homocysteine. OBJECTIVE: We determined whether high concentrations of inflammatory markers are associated with hyperhomocysteinemia independently of dietary vitamin intakes, vitamin concentrations, and cardiovascular disease risk factors in a large, representative sample of the general population. DESIGN: Five hundred eighty-six men and 734 women were randomly selected from the inhabitants of 2 small towns near Florence, Italy. RESULTS: After adjustment for multiple potential confounders, interleukin 1 receptor antagonist (IL-1ra) and interleukin 6 (IL-6) concentrations were significantly (P < 0.001) associated with plasma homocysteine concentrations in older (>65 y) populations. Compared with participants in the lowest IL-6 tertile, those in the highest tertile had a higher risk of having homocysteine concentrations that were high (>30 micromol/L; odds ratio: 2.6; 95% CI: 1.1, 5.6; P = 0.024) or in the intermediate range 15-30 micromol/L (odds ratio: 1.6; 95% CI: 1.2, 2.2; P = 0.0014). Sedentary state, intakes of vitamin B-6 and folic acid, and serum folate, vitamin B-12, vitamin B-6, and alpha-tocopherol concentrations were significant independent correlates of homocysteine. CONCLUSIONS: High circulating concentrations of IL-1ra and IL-6 are independent correlates of hyperhomocysteinemia and may explain, at least in part, the association between homocysteine and atherosclerosis.

Clotting activation after oral anticoagulant therapy discontinuation: a risk factor for recurrent venous thromboembolism.

A hypercoagulable state has been reported in some patients treated for venous thromboembolism (VTE) after oral anticoagulant treatment (OAT) discontinuation. It is unclear whether this is a risk factor for thrombosis recurrence. We investigated 139 patients with VTE and followed them up for a median of 20.5 months (6-90 months) to evaluate whether fragment 1 + 2 (F1 + 2) plasma levels are prognostic for VTE recurrence and to confirm clotting activation after OAT withdrawal. Fourteen patients had recurrences during the follow-up. F1 + 2 was measured the day before OAT withdrawal (T0) and 4 weeks later (T1) and its levels were similar in patients with spontaneous VTE versus those with transient risk factors for VTE. F1 + 2 levels increased from T0 to T1 (P < 0.0005). At T1, F1 + 2 values were significantly higher in patients with recurrence than in those without (P < 0.005). The negative predictive value of normal levels of F1 + 2 at T1 was 95%. In carriers of thrombophilic conditions no correlation was found between F1 + 2 levels and VTE recurrence. The results of this study confirm clotting activation after OAT discontinuation and suggest that higher F1 + 2 plasma levels are an independent risk factor for VTE recurrence.

Low protein Z plasma levels are independently associated with acute coronary syndromes.

Protein Z (PZ) is a single chain vitamin-K-dependent glycoprotein synthesized by the liver. Studies in vivo and in vitro suggest that PZ plays an important role in inhibiting coagulation as it serves as cofactor for the inactivation of factor Xa by forming a complex with the plasma PZ-dependent protease inhibitor. Recently, conflicting findings on plasma PZ levels in patients with ischemic stroke have been published. Aim of our study was to investigate the role of PZ in acute coronary syndromes (ACS). PZ plasma levels were determined in 223 (189 M; 34 F) patients with ACS referring to the Coronary Intensive Therapy Unit of University of Florence and in 265 (219 M; 46 F) healthy subjects. Patients under oral anticoagulation treatment as well as subjects with positivity for antiphospholipid antibodies were excluded. None had liver or kidney dysfunction. The mean PZ plasma level was lower in patients (1508 +/- 730 ng/mL) than in controls (1728 +/- 594 ng/mL) (p < 0.0001). PZ levels below the 5th percentile (565 ng/mL) of normal values distribution in control subjects were found in 15.7% of patients and in 4.9% of controls (p <0.0001). At multivariate analysis, PZ levels below 565 ng/mL were associated with ACS (OR=3.3; 99%CI 1.1-9.7; p = 0.004). The contemporary presence of low PZ levels and smoking habit leads to an increased risk of ACS (OR=9.5; 99%CI 2.4-37.2; p < 0.0001). In conclusion, our results suggest a possible role of PZ in the occurrence of arterial thrombosis.